Questions tagged [iterator]
An iterator is an object-oriented programming pattern which for the most part functions similarly to a pointer to an object inside a collection with the added ability to traverse through the collection in a defined manner, agnostic of the actual implementation or even object addresses in physical memory. Iterators may be further limited in particular traversal directions.
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Finding highly correlated variables in a dataframe by evaluating its correlation matrix's values
I read data from Excel into a Pandas DataFrame, so that every column represents a different variable, and every row represents a different sample. I made the function below to identify potential ...
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Improving efficiency of Rust algorithm ported from Python generator
I'm learning Rust by solving ProjectEuler problems.
To this end, I am trying to port a solution to problem 88 (link) in Python that heavily relies on generators to Rust (which doesn't have generators)....
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Extend iterators with until() function
I want to extend generic iterators with a convenience function until() that works like an inversion of take_while().
Here is the ...
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Max Stack implementation in C++ involving iterators
The tricky thing was keeping copies of list iterators in a tree map and managing both together. I'm not handling invalid input cases (like popping an empty stack) in this code. I am following Google C+...
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Convert Rankine temperatures to Celsius
I have this Python Package called ToTemp under development for precise Temperature Conversions and currently thinking in changing the method's implementation to be ...
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2D Matrix in C++
I wanted to play with a two-dimensional generic data container in C++ and explore different methods of traversals: using closures and iterators. I'd like a review of it.
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Middle of the Linked List in Rust
Yesterday, inspired by some great questions here, I decided to give myself some practice with Rust, by solving all the introductory questions over on LeetCode. It was a great learning exercise, and ...
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2021 Day 1 Advent of Code in Rust
I'm preparing for the Advent of Code 2022, and in order to shake off the cobwebs, I'm attempting some problems from the previous year in rust. Starting at Day 1, I've been trying to get comfortable ...
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Finding the number of possible paths in a cave system (Python)
I've finally come up with working solution for day 12 of AdventOfCode, where you have to find the number of possible paths in a cave system following a given set of rules (described below). My ...
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Dont let duplicated values in Iterator return of a function
I'm trying to build a function to return an Iterator with no duplicated float values, its working, but there is a better way of handling this duplicated values?
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Merge two strictly increasing sequences, without duplicates
This work is motivated by Sum of natural numbers below threshold, where several Swift solutions to Project Euler #1 (with arbitrary upper bound) are provided.
One way to think of it is to
start with ...
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Iterating over all simple unique cycles in an undirected graph in Java - brute-force approach
This post is about an Iterator iterating over simple loops of an undirected graph.
In the above graph, the cycle \$\langle 1, 2, 3, 4, 5, 3, 1 \rangle\$ is not ...
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Implementing Ord trait for an Iterator Wrapper
Recently, I needed to sort iterators by their first value and/or use them in BinaryHeap. There are things I don't like about this implementation:
Using RefCell.
...
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Matrix implementation
I am trying to implement an optimal and fast running matrix in C++. I need some review of the code and ideas on how to improve the code quality if it shall be.
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A prime iterator in JavaScript
This is an implementation of a Sieve of Eratosthenes as [Symbol.iterator] in JavaScript.
Comments welcome, my JS is a bit rusty. Making a class of this is mainly the reason to have fun with the ...
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Find longest palindrome in a string (LeetCode problem 5)
The code below is my solution to the following problem (problem #5 on LeetCode):
Given a string s, return the longest palindromic substring in s.
I wonder whether my use of iterators is an overkill. ...
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Zipping two lists with an offset in Python
Walking my first steps in Python from C, I find myself missing pointers from time to time.
In this case I want to go through a list processing two element at a time, where those elements are step ...
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Action on each element of an inline list
I'm trying to learn the "functional" part of C#/.Net for work, and I'm not sure if this is a good way to write this statement.
I was also trying to reduce duplicated code while not ...
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2d Grid - Iterating by Rows / Cells - Take #3
Edited with a bit more unit tests.
Preface
Following my second version:
2d Grid - Iterating by Rows / Cells - Take #2
I believe that I am now satisfied with this new version below.
There is still one ...
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Prime numbers iterator
I am not familiar with iterators. I am confused with the traits approach and the traditional one. I don't know which one I should use in 2021.
I wrote a minimal ...
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2d Grid - Iterating by Rows / Cells - Take #2
Preface
Following my first POC version:
2d Grid - Iterating by Rows / Cells
I have gained much more understanding, and present
A new version
A new version is ready, with templates and an attempt at ...
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Custom implementation to provide an immutable range of a container without copying it
I needed to pass a const reference to part of a std::vector without copy. I posted the previous version in my earlier question, thank you for the great support! As ...
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2d Grid - Iterating by Rows / Cells
The feature
Here is a Grid class representing a 2d grid.
The class will get templated once it reach a satisfactory state.
At this time the cells are int values.
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Custom implementation to provide an immutable range of a vector without copying it
Edit: A new and improved version can be found in this question, based on the feedback!
I needed to pass a const reference to part of a std::vector without copy.
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A counting loop class v2
Rewrite of A simple counting loop class based on feedback:
This version adds a step parameter and better iterator concept support.
Counting is always done in a signed integral, and only integers and ...
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A simple counting loop class
EDIT: Updated version available here: A counting loop class v2
Ranges (C++20) aren't quite ready, so until then, I needed a reliable counting loop class that works fairly well to replace the old-...
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Single-linked-list in C++ with iterators
I'm implementing a single linked list as close as it could be to std::forward_list. I would welcome a review and also more suggestions on what to test additionally.
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Left Shift/ Right Shift an array in C
I am trying to implement a Left shift/ Right Shift on arrays.
I was able to accomplish this using double loops.
Can the efficiency be improved?
This is the working code for LeftShift/RightShift which ...
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Radio with channels
Realize the Radio and Channel classes that represent radio and a radio station. The radio class offers an argumentless constructor and the following methods:
addChannel: stores and returns a new ...
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Using the Decoder class in a streaming context
Am experimenting with the IAsyncEnumerable interface and PipeReader class. Have come up with the following to decode a stream of bytes into chunks of characters and am able to decode all of my test ...
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Python's enumerate for C++
I implemented an enumerate() method for C++ containers similar to Python's enumerate to iterate through a range with an index and the actual value.
I have the following questions:
Does the usage of ...
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Iterate through non-empty words from text files
Given a file or directory, create an iterator that returns the non-empty words from the file or from all files recursively in the directory. Only process ".txt" files. Words are sequence of ...
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Bidirectional iterate over list in Python
I wrote a short function to iterate over a list starting at a given index, then flipping back and forth between left and right values.
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Iterating 2d array
I have implemented a MatrixIt class to traverse a 2D array. Is it possible to make the code clearer and shorter?
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Scraping odds portal with beautiful soup
This code scrapes www.oddsportal.com for all the URLs provided in the code and appends it to a dataframe.
I am not very well versed with iterative logic hence I am finding it difficult to improvise on ...
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Adding iterators to C++ sqlite wrapper class
I recently put up my C++ class to wrap the sqlite3 c library here:
Thin C++ wrapper for sqlite3 C library
One of the suggestions was rather than to specify a vector for arguments to functions instead ...
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Image (Const) Iterator using C++17
I am trying to learn how to correctly implement an iterator (and its corresponding const variant) using a single template, so I would appreciate any criticism to the following code. It's an forward ...
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Implement a range behaviour in Python using iterators
I've been assigned the following Python homework:
Implement myrange that acts like range using iterators. Define a function ...
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Rcpp sparse CSC matrix class
This is a sparse matrix (dgCMatrix) class that extends Rcpp.
WHAT: This class includes Rcpp::NumericVector and ...
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Racing promises and consuming them in the order of their resolution time
The ideas are
When multiple async calls are made, to be able to start consuming from the first resolving one regardless in what order the promises are fired.
To construct a modern emitter of async ...
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Throttled execution of an enumeration of Tasks
Example of use:
var users = await usernames.SelectTaskResults(GetUserDetails, 4);
where GetUserDetails(string username) is a ...
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A C++ iterator that adds an extra layer of indirection
This iterator is designed with one purpose in mind. If before you had an iterator where you could do
int x = *it;
now you do
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Forward List Implementation
NB: There's a bug with my iterator, apparently. I can't use const_iterator because I get some compiler errors. I know using const...
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How to optimize this majority vote method
I have the following code to do a majority vote for data in a dataframe:
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Random Access Iterator Implementation
(This is the Non-const version, I have to implement the const one too).
Could someone please review this implementation? This is made for std::vector
I'm unsure whether I respected all requirements ...
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Input Iterator implementation
I need some review on my implementation of input iterator. I am currently re-implementing std::vector, and need input_iterator for a specific constructor.
Any criticism is much appreciated! Thank you.
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Cyclic generator with access to current local state and executes callback after each cycle
I'm working on a Python class that is a cyclic generator, like itertools.cycle, but it offers access to its current state and executes a callback after the ...
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wrapper class for random access iterator to hide template method implementation from header file
I have a set of template functions that have itrator types as template parameters, so can be used with any kind of iterators. std::find can be a good example.
Also ...
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Const wrapper for iterator
Edit: added clarification for why I want this, and updated the code since I don't have any answers yet
I have a C++11 array-like class which (can be) a wrapper around a random-access iterator. Index-...
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